LONDON, Nov 28 (Reuters) - Hopes for a thaw in U.S.-China trade relations at the upcoming G20 summit helped world shares inch to a one-week high on Wednesday, though fears of a no-deal outcome weighed on European bourses and kept the dollar firm for the fourth day in a row.

While President Donald Trump talked tough on the trade tariffs issue ahead of a meeting with Chinese President Xi Jinping on Saturday, markets focused on comments by White House economic adviser Larry Kudlow, who held open the possibility that the two countries would reach a trade deal.

But the mood fizzled somewhat into the European session, with the pan-European index giving up opening gains to trade flat and Germany's export-heavy bourse slipping 0.2 percent.

A Tuesday report that Trump may soon decide about new taxes on imported cars, still weighed on sentiment, keeping Europe's auto sector shares 0.6 percent in the red

"An expectation is being priced into markets ahead of the G20 meeting that we will see some deal or at least a framework for a deal between Trump and (Chinese President) Xi Jinping," said Bernd Berg, global macro strategist at Switzerland-based Woodman Asset Management.

"But if they come out with nothing this weekend, it's going to be very bad."

Futures pointed to a marginally firmer open on Wall Street .

The uncertainty over global trade as well as Brexit and Italy's conflict with the European Union, have supported the U.S. dollar, which rose to a two-week high against a basket of currencies.

While the main driver for the greenback is the U.S. interest rate path, Rodrigo Catril, senior strategist at National Australia Bank, said it was also benefiting from the uncertain mood.

"Markets seem to be jumping at shadows at the moment and against this backdrop of uncertainty, the dollar remains the preferred option for weathering the storm," Catril said.

With the currency index approaching 1-1/2-year highs reached earlier this month, traders are focusing on a speech at 1700 GMT by Federal Reserve Chair Jerome Powell to see if he offers clues on how many more times the Fed could raise interest rates.

While Fed Vice Chair Richard Clarida took a less dovish stance on Tuesday than some had expected and backed more rate rises, Powell and his colleagues have in recent weeks alluded to global volatility, leading many to speculate the bank's three-year-long rate rise campaign could pause in 2019. .

Berg said there had been some repricing of rate-rise expectations but said the Fed remained on track to tighten policy in December and early-2019 at least.

"My base case is the dollar will strengthen versus the euro and pound into year-end, as the euro zone and Britain are both struggling with their own problems -- Brexit and Italy," Berg said.

Sterling was flat around $1.2754, just off two-week lows, as British Prime Minister Theresa May battles to convince sceptical voters, lawmakers and businesses of the benefits of her Brexit deal.

May needs to win a Dec. 11 parliamentary vote on the deal she has negotiated with the EU to exit the bloc but with most parties opposed, that looks unlikely.

The euro is languishing at $1.1286, also near two-week lows to the dollar.

Italian bond yields flatlined after sharp rallies that were triggered by what appeared to be a more conciliatory stance from the government over the issue.

On other markets, cryptocurrency bitcoin jumped 6 percent to above $4,000, extending its rebound from a low of $3,475 touched on Sunday.

Brent oil futures rose almost one percent ahead of next week's OPEC meeting at which the producer club could decide on supply cuts to counter a crude glut.. But prices are still down by almost one-third since early October.

Reporting by Sujata Rao; additional reporting by Swati Pandey
in Sydney and Hideyuki Sano in Tokyo; editing by Louise Heavens